Property Documentation & Garage Non allotment.

Dear Sir, I have an ancestral property (flat) which is located in Kolkata and my fathers make a joint venture agreement with a builder on 2013. As per the agreement we will get a flat & a car parking space. In the year 2020 after discussion with the builder we enter the flat and started staying with family. But our builder not providing any types of property related documents such as Registration Certificate, Mutation Certificate, Flat Handover / Possession Letter, Building Plan, Building CC etc. We have several times communicate him but he is not providing the same. Garage / Car Parking issue : After so many verbal discussion had with him the car parking space which he supposed to allot us is now being sold to other and he is now trying to allot me another space for garage / car parking which is in front of main entry gate of the building and in front of staircase & lift area. That space can create lots of obstructions to other flat owners as well as against fire safety rules. Kindly guide me what can I do for it.